Background

It is unclear whether the serum prolactin (PRL) surge following electroconvulsive therapy (ECT) is a marker of optimal ECT administration. We investigated the relations among PRL surge, stimulus parameters, and outcome in major depressive disorder (MDD).

Methods

Seventy-nine patients with MDD were randomized in a double-blind trial to right unilateral (RUL) or bilateral (BL), and to low-dose (just above seizure threshold) or high-dose (2.5 x threshold) ECT.

Results

Change in PRL (delta PRL) varied among treatment groups, with significant effects of electrode placement (BL > RUL, p < .006), electrical dosage (high > low, p < .04), and gender (female > male, p < .005). There was no evidence that clinical improvement was associated with greater PRL surge.

Conclusions

Although delta PRL varied with parameters impacting on response rates, these data indicate the PRL surge cannot serve as a useful index of clinically effective treatment. This finding does not support the view that diencephalic seizure propagation is necessary for ECT to exert therapeutic effects.